The specific aims of the Neuropathology Core are to establish accurate, comprehensive neuropathological diagnoses using strict, reliable diagnostic criteria and to precisely document the neuropathological findings on all brains of enrolled patients and elderly normal subjects followed at the Bedford VAMC and at the Boston University Home Medical Service (HMS). These intensive neuropathological analyses - including quantitative histopathological, anatomical and immunocytochemical evaluations - will facilitate clinicopathological correlative studies of the functional, behavioral, and neuropsychiatric aspects of Alzheimer's disease (AD). In addition, the Neuropathology Core will establish the Boston University Brain Tissue Resource Center as a source of fresh, fixed and deep frozen brain tissue for investigators studying AD. A Rapid Autopsy Protocol has been designed that will ensure high quality fresh, fixed and frozen tissue to investigators requiring tissue with brief post- mortem intervals. A computerized database will be maintained under the direction of the Administrative Core to include all clinical and pathological diagnoses, neuropathological data, cause of death, post- mortem interval, associated chronic diseases, and storage conditions of the tissue. Tissue availability and distribution will also be monitored using a computer program specifically developed for this project. Quality assurance in tissue procurement, handling, processing, storage, and neuropathological diagnosis will be provided by a weekly meeting of the five-member Neuropathology board. Prioritization of requests for tissue and other materials will be supervised by the Brain Tissue Resource Committee. The autopsy rate on patients from the Dementia Study Units currently averages 72%. A concerted effort will be made to obtain brain donations from as many HMS patients as possible using educational approaches focused on care providers, especially medical students and patients families, in conjunction with the Education and Information Transfer Core. As a further aim, the Neuropathology Core will provide well-characterized blood-brain endothelial cells obtained from post-mortem donors, for researchers who wish to carry out AD-related studies on cultured living cells.